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Conditioning. Neutral stimulus CS (tone). CR (salivation). +. UCS (food powder). After conditioning. CS (tone). CR (salivation). Prior to conditioning. (Orientation to sound but no response). Neutral stimulus (tone). UCS (food powder in mouth). UCR (salivation).
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Conditioning Neutral stimulus CS (tone) CR (salivation) + UCS (food powder) After conditioning CS (tone) CR (salivation) Prior to conditioning (Orientation to sound but no response) Neutral stimulus (tone) UCS (food powder in mouth) UCR (salivation)
Watson & Raynor • Human fears can be acquired through Pavlovian conditioning. • Rat paired with loud noise • Stimulus generalized to other white objects (white rabbit, white fur coat) • Mary Cover Jones developed a technique for eliminating conditioned fears. • Acquisition of fear-inhibiting response
Modification of Instinctive Behavior Chapter 2
Instinctive Systems • Lorenz & Tinbergen – evolution occurs when a species incorporates environmental knowledge into its genetic structure. • Greylag goose and egg-rolling. • Learning can sometimes modify instinctive behavior – even though the fixed action patterns are innate.
Energy Model • Action-specific energy builds up but is blocked (inhibited). • The energy motivates appetitive (approach) behavior. • Presence of a sign stimulus releases the energy by stimulating an innate releasing mechanism. • The behavior occurs as a fixed action pattern (or chain of actions).
Releasing Signs • Releasing signs can be complex: • Grayling butterfly signs include darkness of female, distance from male, and pattern of movement. • Intensity of the sign influences the behavior but so does the amount of accumulated energy (time since the last response).
Hierarchical System • Specific behaviors are controlled by a central instinctive system. • Energy can accumulate at each level in the system. • Hormones generate energy. • Release of energy at higher levels flows to lower levels. • The sign stimulus determines which behavior will occur.
Conflicting Motives • If two incompatible signs appear at the same time, energy flows to a third instinct system. • This third behavior is called displacement.
Conditioning Affects Behavior • Conditioning experiences can change sensitivity to releasing signs. • Only the consummatory response at the end of a chain cannot be changed. • Conditioning fine tunes the response to the environment and enhances survival.
Criticisms of the Energy Model • Best viewed as a metaphor. • The brain does not literally accumulate energy in any centers and nothing flows. • Willows & Hoyle – alternating contractions in sea slug allow it to escape from a starfish. • Brain areas producing this response do not correspond to energy model.
Acquired Changes in Response • Habituation – response to a repeated stimulus decreases with experience. • Sensitization – response to a repeated stimulus increases with experience. • Examples: • Ingestional neophobia, fear of new food • Startle response
Experimental Evidence • Rats drink little saccharin water at first but increase over time. • Loud tones (110 db) produce different responses depending on the background noise (60 vs 80 db). • Habituation occurred at 60 db • Sensitization occurred at 80 db • A loud background is arousing, leading to greater reactivity, not less.
Conditions Producing Change • More intense (stronger) stimuli produce stronger sensitization, less likely to produce habituation. • Greater sensitization and habituation occur when the stimulus is repeated frequently. • Changes in the stimulus prevent habituation. • Turkeys respond to shape changes.
Conditions (Cont.) • Sensitization can occur to many kinds of stimuli but habituation occurs only with innate responses. • Habituation and sensitization are transient (go away after seconds or minutes between stimuli). • Except long-term habituation. • Dishabituation – response returns when a sensitizing stimulus occurs.
Opponent-Process Theory • An explanation for addictions. • All experiences produce an affective reaction (pleasant or unpleasant) – A state. • This reaction gives rise to its opposite – B state. • B state is less intense and lasts longer. • Over time, the A state diminishes and the B state increases.
The Addiction Process • Tolerance – diminished A state. • Withdrawal – increased B state. • Addictive behavior is a coping response to the change in B state. • People try to enhance A state to offset the unpleasantness of the B state. • Without withdrawal symptoms there is no addictive behavior. • Time prevents B state strengthening.
What Sustains Addiction? • The B state is a non-specific aversive feeling. • Anything similarly aversive will motivate the addictive behavior, even if it has no relation to the substance. • Daily life stress produces a B state that results in behavior to create an A state. • Parachute jumpers – create a B state in order to feel the A state.